如何为Plotly Density Mapbox密度地图添加美国县界边界图层

你只需要在mapbox_layers配置项中新增一个矢量图层加载美国县界的GeoJSON数据即可，完整可运行代码如下：

import plotly.express as px
import pandas as pd
import json

# 示例数据
df = pd.DataFrame(data=([[32.4087249155, -100.9509696428, '2013-01-01', 1],
       [31.5201976084, -102.1030942593, '2013-01-01', 1],
       [31.434573418, -102.0592907601, '2013-01-01', 1],
       [31.2635930582, -101.95341361, '2013-01-01', 1],
       [31.4287233847, -102.0253840388, '2013-01-01', 1],
       [31.4872286706, -101.5455598032, '2021-01-01', 1],
       [31.5439162579, -101.4833865708, '2021-01-01', 1],
       [31.5439362581, -101.4833065695, '2021-01-01', 1],
       [31.7980713977, -102.0937650441, '2021-01-01', 1],
       [32.02050082, -103.31736372, '2021-01-01', 1]]), 
        columns=['Latitude', 'Longitude', 'Date', 'Count'])

# 读取本地存储的美国县界GeoJSON文件，该公开数据可从美国人口普查局官方渠道获取
with open('us_counties.geojson', 'r', encoding='utf-8') as f:
    us_counties_geojson = json.load(f)

fig = px.density_mapbox(df,
                        lat='Latitude', lon='Longitude', z='Count',
                        radius=10,
                        zoom=3,
                        height=700,
                        animation_frame='Date',
                       )
fig.update_layout(
    mapbox_layers=[
        # 原有USGS卫星底图层
        {
            "below": 'traces',
            "sourcetype": "raster",
            "sourceattribution": "United States Geological Survey",
            "source": [
                "https://basemap.nationalmap.gov/arcgis/rest/services/USGSImageryOnly/MapServer/tile/{z}/{y}/{x}"
            ]
        },
        # 新增美国县界图层
        {
            "below": 'traces',
            "sourcetype": "geojson",
            "source": us_counties_geojson,
            "type": "line",
            "color": "#888888",
            "line": {"width": 0.8}
        }
        ],
    mapbox_style = "white-bg"
)

fig.show()

参数调整说明 #

• 若希望县界显示在密度热图上方，删除新增图层的"below": 'traces'配置即可
• 可通过修改color和line.width参数调整边界的颜色和粗细，适配不同底图风格

内容的提问来源于stack exchange，提问作者tchanque